1. Field of the Invention
A catalytic process, including a new catalyst, for the catalytic dehydrogenation of cyclohexanol to cyclohexanone.
2. Description of the Prior Art
Industrially, cyclohexanol is converted to cyclohexanone in the presence of a copper catalyst at temperatures of 220.degree. to 260.degree. C. or 350.degree. to 450.degree. C. The low temperature conversion, in the prior art results in low throughput, and the catalyst may be subject to deactivation by the water produced as a by-product of the reaction. The hydrolysis of the catalyst by the water vapor may also fracture the catalyst and build up the pressure drop. A high temperature conversion catalyst enables nearly complete conversion of cyclohexanol to cyclohexanone; however, this often causes undesired production of phenol and cyclohexene, resulting in an efficiency loss.
Copper oxide-zinc oxide catalysts have been reported in several literature and patent references namely, A. Sputa et al, Czechoslovakia Patent 151,166, Dec. 15, 1973 (CA 80: 145,560); Mitsubishi Chemical Industries Co., Ltd., Japanese Kokkyo Koho 80/136,241, Oct. 23, 1980 (CA 94: 156,414); R. I. Belskaya et al., Inst. Fiz., Org. Khim., Minsk, USSR 1981 (CA 96: 103,707); N. P. Emelyanov et al., Dokl. Akad. Nauk Beloruss. SSR 11(3), 233 (RUSS) 1967 (CA 67: 108,283); N. P. Emelyanov et al., Dokl. Akad. Nauk Beloruss., French Pat. No. 2,030,602, Nov. 13, 1970 (CA 75: 48,542), U.S. Pat. No. 3,652,460, Mar. 28, 1972 (CA 76: 145,400) V. S. Komarov et al., Dokl. Akad. Nauk Beloruss USSR Pat. No. 660,701, May 5, 1979 (CA 91: 39,009); V. S. Komarov et al., Dokl. Akad. Nauk Beloruss. SU 978,909, Dec. 7, 1982 (CA 98: 160,232). Disclosures relative to adding water to the feedstock to enhance selectivity and conversion rate appear in Ruhrchemie AG British Pat. No. 1,444,484 and UBE Industries, Ltd. Japanese Patent Kokai 73/29,742, Apr. 19, 1973.
As mentioned above, the known types of copper oxide-zinc oxide catalysts often bring about the formation of undesirable cyclohexene and phenol. Accordingly, some of these were promoted with calcium, barium-ruthenium metals to modify the catalytic properties.